Ultrasonic bonding or welding is known. For example, in the aforementioned U.S. Pat. No. 3,419,447 to Hewitt there is described a method and apparatus for bonding thermoplastic sheets to one another wherein adjacent marginal regions of the sheets are overlapped to form an area of double thickness and this overlapping area is then passed between a pair of ultrasonically vibrating tools. The tools compress and heat an intermediate portion of the overlapping area and are constructed and arranged to concurrently (1) transpose the sheets into a common plane, (2) bond the sheets to one another in the intermediate portion, and (3) cut off a pair of unbonded edge portions of the marginal regions at the opposite sides of the bonded portions thereof and at the opposite faces of the sheets, respectively.
Also, in the aforementioned U.S. Pat. No. 3,939,033 to Grgach, there is described an ultrasonic welding and cutting apparatus using an ultrasonically vibrating horn and an anvil means.
Also, in the aforementioned U.S. Pat. No. 4,532,166 to Thomsen there is depicted in FIGS. 1-2 and described in col. 2, lines 22-59 an ultrasonic welding apparatus including an ultrasonic horn 12 vibrating along a vertical axis 14. The edge 16 of a thermoplastic web 18 is supported by the upper surface of an included anvil 10 and the edge 20 of the web 22 is positioned so that the edge 20 of the web 22 overlaps the edge 16 of the web 18. Edge 20 of web 22 contains plural apertures 24. The high vibration frequency of the horn 12 causes the temperature of at least the contiguous overlapping surfaces of the thermoplastic web 18 and web 22 to increase until at least the thermoplastic material in web 18 flows and fill apertures 24. A sectional view of the resulting bonded joint or seam is shown in FIG. 3.
Also, in the aforementioned U.S. Pat. No. 4,878,985 to Thomsen there is described a process and apparatus for fabricating belts utilizing ultrasonic welding. For example, an ultrasonic belt welding station 12 comprising an ultrasonic horn and transducer assembly 300 is described in connection with FIGS. 1, 11, 12 and 13; especially see the written description from col. 14, line 43 to col. 17, line 5.
Also, in the aforementioned U.S. Pat. No. 6,815,131 B2 to Darcy, III, there is described a process of forming a flexible belt utilizing an ultrasonic welding system 70. The ultrasonic welding system 70 is depicted in FIG. 4. As depicted in FIGS. 4-7 and described in the written description at col. 4, lines 18-40, there is provided a flexible belt member 105 having a first end 110 and a second end 120. The first end 110 overlaps the second end 120 and forms an overlap region. In turn, the first and second ends 110 and 120 are ultrasonically welded at one or more locations along the overlap region, thus forming a finished belt. One example of a finished belt 100 is shown in FIG. 8.
Using mandrels in forming endless belts is known. In the aforementioned U.S. Pat. No. 3,799,859 to Wallin, for example, there is described a method and apparatus for forming a relatively thin, flexible endless belt on a support mandrel. After the endless belt is formed, the belt is removed from the mandrel.
Also, in the aforementioned U.S. Pat. No. 5,693,372 to Mistrater, there is described a process for dip coating a drum substrate 23. As depicted in FIG. 2 and described in the written description from col. 6, line 40 to col. 7, line 5, the drum substrate 23 is suspended from a mandrel 25 which grips the interior surface of the drum substrate 23.
Using vacuum apertures to secure or hold a belt material during ultrasonic welding is known. In the aforementioned U.S. Pat. No. 4,959,109 to Swain, for example, col. 3, lines 37-60 describe using a vacuum slot 29 to hold a free end of web 6 at a wrapping station 2. The vacuum slot 29 may alternately comprise one or more rows of holes of any suitable shape.
Further, Swain's written description from col. 4, line 59 to col. 5, line 7 describes a vacuum pick up arm 50 including a vacuum chamber 56 coupled to vacuum slots 59, 60 and 61. If desired, additional rows of slots or other suitably shaped apertures may be substituted for vacuum slots 59, 60 and 61.
Further, Swain discloses parallel rows of ports 90, 91 and 92 positioned axially along the outer periphery of mandrel 80. These ports 90, 91 and 92 are connected through airways 93, 94 and 96 that extend from the ports 90, 91 and 92 through shaft 82 to circumferential channels 98, 100 and 102 which, in turn, are connected through corresponding air lines through a journal box 84 to a cluster of electrically activateable valves and switches 105. Positive pressure, a vacuum or ambient air pressure may be supplied to the journal box 84 from any suitable conventional source, Swain, col. 6, lines 14-46.
Although Swain's mandrel 80 is illustrated as a cylinder having a circular cross section, the cross section may be of any other suitable shape. Also, the location of the web seam 138 on the mandrel is preferably positioned parallel to the axis of the mandrel along an imaginary line or band on the outer periphery of the cylinder defined by the greatest radius of the cylinder, Swain, col. 6, lines 55-64.
Further, Swain's web 6 is placed over parallel rows of ports 90 and a vacuum is supplied to the parallel rows of ports 90 to secure the web 6 to the mandrel 80, Swain, col. 7, lines 65-68.
As Swain's mandrel 80 nears the end of its rotation cycle, a vacuum is supplied to parallel rows of ports 92 which anchors the adjacent region of web 6 to mandrel 80 to ensure that web 6 remains tightly wrapped under tension on the mandrel 80 even after a subsequent web cutting operation, Swain, col. 8, lines 17-22.
When Swain's mandrel 80 completes its rotation cycle of 360 degrees, a vacuum is supplied to secure web 6 to support platform 28; pneumatic cylinder 78 is activated to extend disk knife 79 through web 6 and against edge 26; and electric motor 72 is started to rotate lead screw 71 to reciprocate carriage 77 and disk knife 79 across the width of web 6 thereby severing web 6, col. 8, lines 22-29. Upon completion of shearing, a vacuum is supplied to the ports 91 to suck and tack the freshly severed trailing end of web 6 against mandrel 80, the freshly severed trailing end of the web 6 overlapping the leading end to form a seam 138, Swain, col. 8, lines 32-38.
Further, Swain's written description from col. 9, line 38 to col. 10, line 1 describes an ultrasonic welding station 3 comprising an ultrasonic horn 136. The seam 138 of overlapping ends of thermoplastic web 6 is supported by mandrel 80 and held in place below the path of ultrasonic horn 136 by suction from parallel rows of ports 90, 91 and 92, col. 9, lines 38-45. The ultrasonic horn 136 traverses the seam 138, col. 9, lines 65-68; col. 10, line 1, thereby welding the seam 138, from col. 11, line 13 to col. 12, line 2. See also Swain, col. 22, lines 3-32.
Also, the aforementioned U.S. Pat. No. 5,085,719 to Eck describes at col. 5, lines 15-22 a web lap joint 24 formed by the overlapping segment ends of thermoplastic web 12 that is supported by the upper surface of anvil 14 and held in place below the path of ultrasonic horn and transducer assembly 30 by suction from parallel rows of grooves 33, 34, 36 and 38 in the upper surface of anvil 14, the grooves leading to vacuum plenums within the interior of the anvil 14.
Further to Eck, col. 6, lines 1-16 describe applying vacuum to grooves 33, 34, 36 and 38 to hold the overlapping opposite edges 20 and 22 of web 12 in place during ultrasonic welding. As described, the length of grooves 33, 34, 36 and 38 is normally slightly shorter than the width of web 12. Any suitable vacuum aperture, such as grooves or holes, may be utilized. See also the “example” described from col. 13, line 30 to col. 14, line 30.
A new polymeric material named “Kapton®” has been developed jointly by DuPont® and Xerox® Corporation for intermediate transfer belts. Note that the registered trademark “DuPont” is owned by E. I. du Pont de Nemours and Company, Wilmington, Del.
It has been discovered that the same Kapton® material works nicely for fuser belts. These fuser belts are ultrasonically welded, then super-finished to disguise the welded seam area. The foregoing super-finishing may be accomplished by any convenient super-finishing process. See, for example, the super-finishing processes described in the aforementioned U.S. Pat. No. 6,848,978 B2 to Mastro.
One problem in fabricating the fuser belts with the Kapton® material, however, is that fuser belts are very small in circumference. The current fuser belts used in one application are only 30 milli-meters (“mm”) in diameter or 3.70 inches in circumference. In contrast, conventional belt fabrication processes are only capable of making belts as small as 18.00 inches in circumference.
Due to the beam strength of the Kapton® material, its bend radius is such that the material will not lay flat when wrapped around a 30 mm diameter mandrel with a 0.25 inch-wide weld flat ground for ultrasonically joining the overlapped material. As depicted in the present FIG. 1, one problem is that the material tends to tent up, as depicted by reference number 2 in the present FIG. 1, and there is no way to get vacuum apertures 6 in close enough to the overlap area to hold the material down. This tenting is due to the beam strength of the material 20 to be welded relative to the radius of curvature of the belt.
Thus, there is a need for the present invention.